1. Field of the Invention
The present invention relates broadly to stepper motors or other step-motion actuators and mechanisms for accomplishing stepped motion. More particularly, the present invention concerns a stepper motor or other step-motion actuator that uses piezoelectric material to launch one or more flight masses, which, in turn, actuate a drive pawl to progressively engage and drive a toothed wheel or rod to accomplish stepped motion. Thus, the piezoelectric material converts electrical energy into kinetic energy of the masses, and the drive pawl and toothed wheel or rod convert the kinetic energy of the masses into the desired rotary or linear stepped motion.
2. Description of the Prior Art
It is often desirable to use stepper motors or other step-motion actuators to achieve highly predictable and controllable stepped motion, particularly in micro- and nano-sized mechanisms. To that end, a variety of electrostatic, electromagnetic, and piezoelectric concepts have been devised to accomplish stepped motion within such small-scale actuators. In general, however, step-motion actuators using these concepts are in the early stages of development and still suffer from a number of problems and disadvantages. For example, energy density in these step-motion actuators is typically too low to be useful. Also, none of the current concepts have proven to be universally applicable.
Due to the above-identified and other problems and disadvantages encountered in the prior art, a need exists for an improved step-motion actuator.